Sex differences in personality are larger in gender equal countries: Replicating and extending a surprising finding

Sex differences in personality have been shown to be larger in more gender equal countries. We advance this research by using an extensive personality measure, the IPIP‐NEO‐120, with large country samples (N > 1000), from 22 countries. Furthermore, to capture the multidimensionality of personality we measure sex differences with a multivariate effect size (Mahalanobis distance D). Results indicate that past research, using univariate measures of effect size, have underestimated the size of between‐country sex differences in personality. Confirming past research, there was a strong correlation (r = .69) between a country's sex differences in personality and their Gender Equality Index. Additional analyses showed that women typically score higher than men on all five trait factors (Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness), and that these relative differences are larger in more gender equal countries. We speculate that as gender equality increases both men and women gravitate towards their traditional gender roles.     

Gender-stereotyped preferences in childhood and early adolescence: A comparison of cross-sectional and longitudinal data

Children are exposed to a gender-specific environment on an everyday basis through media, books, school supplies and especially toys. Children’s movies and television programs were found to portray protagonists’ occupational and private roles in a very traditional, gender-stereotypical way. The present two studies aimed to investigate gender-specific preferences in childhood and early adolescence. Cross-sectional data (study 1) were compared to longitudinal one (study 2) as we specifically aimed to investigate changes in gender preferences over time. A person-oriented approach, namely Configural Frequency Analysis was applied, to categorically analyze the relationship and development of gender-stereotyped preferences throughout childhood and early adolescence. Consistent with former studies, study 1 showed that gender-stereotypical preferences increased by age, for boys to a higher extent than for girls. By the age of twelve, these preferences had decreased supporting the theory of Kohlberg that children’s gender-stereotypic preferences continuously grow until around six years of age to finally lower thereafter. Gender-specific preferences generally became much more flexible over time.     

Refining the psychometric properties of the circadian type inventory

The psychometric properties of the 18-item circadian type inventory (CTI) were examined in a non-shiftwork sample. Inter-item correlations for each scale were low to moderate. Confirmatory factor analysis (CFA) via structural equation modelling did not support the posited structure of the CTI. Principal components analysis and reliability analyses suggested the CTI is better represented by 11-items. The revised five item FR scale accounted for 27% of the variance, had stronger factor loadings and increased Cronbach alpha. The psychometric properties of the six item LV scale were marginally improved and explained 21% of the variance. The two-factor 11-item model was supported by CFA. Compared to the 18-item model, the 11-item model showed a marked improvement on several incremental fit indices and achieved a more parsimonious model fit. There was some indication of gender differences but a multi-group CFA indicated model parsimony was best for the invariant model. Gender difference needs to be further examined in large samples using a similar gender balance. It is concluded that the 11-item CTI is psychometrically superior to the original. However, its predictive efficacy needs to be examined in longitudinal studies.     

Sex differences in general knowledge in German high school students

This study examines the hypotheses that (1) 17 domains of general knowledge can be identified; (2) these are positively intercorrelated and form a general factor of general knowledge; (3) there are sex differences in the different domains of general knowledge; and (4) males have more general knowledge in more of these domains than females and in the general factor. The study tests these hypotheses on a sample of 302 German high school students. All the hypotheses were confirmed. All the domains of general knowledge were positively intercorrelated. A general factor was found that explained 31.3% of the variance. Males achieved significantly and substantially higher scores than females in general knowledge of 0.60d. The only area in which females scored significantly higher than males was Nutrition for which there was a medium size effect size (d=0.50). The results are highly similar to those among university students in Northern Ireland reported by Lynn, Irwing, and Cammock (2002).     

Sex differences in dichotic listening

The present study quantified the magnitude of sex differences in perceptual asymmetries as measured with dichotic listening. This was achieved by means of a meta-analysis of the literature dating back from the initial use of dichotic listening as a measure of laterality. The meta-analysis included 249 effect sizes pertaining to sex differences and 246 effect sizes for the main effect of laterality. The results showed small and homogeneous sex differences in laterality in favor of men (d=0.054). The main effect of laterality was of medium magnitude (d=0.609) but it was heterogeneous. Homogeneity for the main effect of laterality was achieved through partitioning as a function of task, demonstrating larger asymmetries for verbal (d=0.65) than for non-verbal tasks (d=0.45). The results are discussed with reference to top-down and bottom-up factors in dichotic listening. The possible influence of a publication bias is also discussed.     

Inhibitory control and empathy-related personality traits: sex-linked associations

We here report two studies exploring associations between inhibitory control (measured with the Sustained Attention to Response Task, SART) on the one hand, and self-reports of trait cooperativeness and empathy on the other. A coherent picture was obtained in women whose inhibitory control proficiency predicted higher scores on the Temperament and Character Inventory Cooperativeness and a higher Empathy Quotient. Individual differences in working memory did not predict self-reported empathy. In men, the association between SART performance and empathy was less clear: Good performance on the inhibitory task predicted lower scores on Cooperativeness and was unrelated to the Empathy Quotient. In both studies, women outperformed men on the SART. The results in women may reflect how individual differences in elemental neuro-cognitive operations such as inhibitory control influence more complex functions such as social cognition.     

Examining the sex- and circadian dependency of a learning phenotype in mice with glycine transporter 1 deletion in two Pavlovian conditioning paradigms

Behavioural characterisation of transgenic mice has been instrumental in search of therapeutic targets for the modulation of cognitive function. However, little effort has been devoted to phenotypic characterisation across environmental conditions and genomic differences such as sex and strain, which is essential to translational research. The present study is an effort in this direction. It scrutinised the stability and robustness of the phenotype of enhanced Pavlovian conditioning reported in mice with forebrain neuronal deletion of glycine transporter 1 by evaluating the possible presence of sex and circadian dependency, and its consistency across aversive and appetitive conditioning paradigms. The Pavlovian phenotype was essentially unaffected by the time of testing between the two circadian phases, but it was modified by sex in both conditioning paradigms. We observed that the effect size of the phenotype was strongest in female mice tested during the dark phase in the aversive paradigm. Critically, the presence of the phenotype in female mutants was accompanied by an increase in resistance to extinction. Similarly, enhanced conditioned responding once again emerged solely in female mutants in the appetitive conditioning experiment, which was again associated with an increased resistance to extinction across days, but male mutants exhibited an opposite trend towards facilitation of extinction. The present study has thus added hitherto unknown qualifications and specifications of a previously reported memory enhancing phenotype in this mouse line by identifying the determinants of the magnitude and direction of the expressed phenotype. This in-depth comparative approach is of value to the interpretation of behavioural findings in general.     

Disentangling the relationship between hemispheric asymmetry and cognitive performance

It is widely believed that advantages of hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between hemispheric asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a corresponding task. Yet, the empirical evidence for this notion is mixed and the statistical methods to analyze this relationship have been criticized. The present study therefore investigated the relationship between hemispheric asymmetries and cognitive performance in two behavioral tasks (a left-lateralized word-matching task and a right-lateralized face-decision task) in 230 participants (140 women, 90 men) by using two different approaches. Both methods correspondingly revealed that a relationship between hemispheric asymmetries and cognitive performance does exist. Contrary to a positive (linear) relationship however, the data could be best described by an inverted U-shaped curve. Although the optimal degree of lateralization seemed to be task-specific, a slight or moderate degree of hemispheric asymmetry achieved best cognitive performance in all tasks. Moreover, performances deteriorated towards extreme ends of lateralization (i.e., participants with either extreme left or right hemispheric biases). Taken together, the present study provides evidence against the notion that higher lateralization is related to enhanced cognitive performance.     

How impulsiveness, trait anger, and extracurricular activities might affect aggression in school children

Individual differences in personality traits such as impulsivity and trait anger as well as environmental variables have an impact on aggressiveness. We tested a model incorporating the related variables of impulsiveness, trait anger, and aggression and incorporated the possible mediating influences of leisure-time activities. Regression analyses of data from 1129 pre-adolescents and 1093 adolescents (55.4% females) from a study evaluating the Spanish version of the Buss and Perry aggression questionnaire (AQ; Santisteban, Alvarado, & Recio, 2007) showed a relation between impulsiveness (Barratt Impulsiveness Scale) and aggression (AQ). Trait anger (Spielberger’s State-Trait Anger Expression Inventory), the time spent watching TV and playing video games, and the time spent doing homework (all related to impulsiveness) also are related to physical, as well as verbal aggression (with low to moderate coefficients). Multiple mediation analyses confirm that media violence exposure and homework, respectively, can have aggravating and attenuating effects on self-reported aggression. These results provide key variables for longitudinal studies which could reveal the causal nature of the results found with our cross-sectional design.